Dataset Information

Trends in medical and nonmedical immunization exemptions to measles-containing vaccine in Ontario: an annual cross-sectional assessment of students from school years 2002/03 to 2012/13.

ABSTRACT:

Background

Under Ontario legislation, for select vaccine-preventable diseases nonimmunized or under-immunized students must undergo vaccination or provide a statement of exemption, or risk suspension from school. At the time of this assessment, these diseases included measles, mumps, rubella, diphtheria, tetanus and polio.

Methods

Exemptions data for the school years 2002/03 to 2012/13 were obtained from the Immunization Records Information System used in Ontario. Temporal trends were expressed for 7- and 17-year-old students by exemption classification (medical, prior immunity, religious or conscientious belief, total) at the provincial level, by school year and by birth cohort. Regional analysis was conducted for the 2012/13 school year. A temporal trend analysis of exemptions for measles-containing vaccines was performed by using a Poisson distribution with a 2-sided test (α = 5%).

Results

For both 7- and 17-year-old students, religious or conscientious exemptions for measles-containing vaccines significantly increased over the study period (p < 0.001 in both age groups), whereas medical exemptions decreased (p < 0.001 in both age groups). The trends were reproduced when examined by birth cohort. The percentage of Ontario students with any exemption classification (total exemptions) remained low (< 2.5%) during the study period, although considerable geographic variation was noted.

Interpretation

Ontario data suggest that nonmedical exemptions have increased during the last 11 years, consistent with trends reported elsewhere. The trend toward increasing religious or conscientious exemptions coupled with declining medical exemptions explains why total exemptions have remained stable or decreased at the provincial level. The prominent geographic variability in exemptions suggests that targeted interventions may be suitable for consideration.

SUBMITTER: Wilson SE

PROVIDER: S-EPMC4596119 | biostudies-literature | 2015 Jul-Sep

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Trends in medical and nonmedical immunization exemptions to measles-containing vaccine in Ontario: an annual cross-sectional assessment of students from school years 2002/03 to 2012/13.

Wilson Sarah E SE Seo Chi Yon CY Lim Gillian H GH Fediurek Jill J Crowcroft Natasha S NS Deeks Shelley L SL

CMAJ open 20150717 3

<h4>Background</h4>Under Ontario legislation, for select vaccine-preventable diseases nonimmunized or under-immunized students must undergo vaccination or provide a statement of exemption, or risk suspension from school. At the time of this assessment, these diseases included measles, mumps, rubella, diphtheria, tetanus and polio.<h4>Methods</h4>Exemptions data for the school years 2002/03 to 2012/13 were obtained from the Immunization Records Information System used in Ontario. Temporal trends ...[more]

PMID: 26457292

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Project description:BackgroundIn Canada, increasing numbers of women, especially First Nations women, are affected by diabetes during pregnancy, which is a major risk factor for adverse maternal and neonatal outcomes. The aim of this study was to examine temporal trends in pregnancy outcomes and use of health care services in a population-based cohort of First Nations women compared to other women in Ontario according to diabetes status during pregnancy.MethodsUsing health administrative databases, we created annual cohorts of pregnant women from 2002/03 to 2014/15 and identified those with preexisting diabetes and gestational diabetes. We used the Indian Register to identify First Nations women. We estimated rates of adverse maternal and infant outcomes, and measures of use of health care services in each population.ResultsThere were 1 671 337 deliveries among 1 065 950 women during the study period; of these deliveries, 31 417 (1.9%) were in First Nations women, and 1 639 920 (98.1%) were in other women. First Nations women had a higher prevalence of preexisting diabetes and gestational diabetes than other women in Ontario. First Nations women with preexisting diabetes had higher rates of preeclampsia (3.2%-5.6%), labour induction (33.4%-42.9%) and cesarean delivery (47.8%-53.7%) than other women in Ontario, as did First Nations women with gestational diabetes (3.2%-4.7%, 38.5%-46.9% and 41.4%-43.4%, respectively). The rate of preterm birth was similar between First Nations women and other women in Ontario. Although First Nations women had a higher rate of babies who were large for gestational age than other women, regardless of diabetes status, obstructed labour rates were similar for the 2 cohorts. Almost all First Nations women, regardless of diabetes status, were seen by a primary care provider during their pregnancy, but rates of use of specialty care were lower for First Nations women than for other women. Fifteen percent of all pregnant women with preexisting diabetes visited an ophthalmologist during their pregnancy.InterpretationOur results confirm disparities in maternal and neonatal outcomes between First Nations women and other women in Ontario. Access to primary care for pregnant women seemed adequate, but access to specialized care, especially for women with preexisting diabetes, needs to improve.

Project description:BACKGROUND:Vaccine hesitancy continues to be an issue throughout the United States, as numerous vaccine hesitant parents are choosing to exempt their children from school-entry vaccination requirements for nonmedical reasons, despite the safety and effectiveness of vaccines. We conduct an analysis of how vaccine refusal, measured by the use of nonmedical exemptions (based on personal or religious beliefs) from vaccination (NMEs), evolved across space and over time in California. METHODS:Using school-entry data from the California Department of Public Health, we examined NMEs for students entering kindergarten in California from 2000 to 2013. We conduct global and local spatial autocorrelation analysis to determine whether NME use became more geographically clustered over the study period and whether the location of local clusters of high use were temporally stable. We conducted a grouping analysis that identified the general temporal trends in NME use over the time period. RESULTS:The use of NMEs increased from 0.73% of all kindergarteners in 2000 to 3.09% in 2013 and became more geographically clustered over the study period. Local geographic clusters of high use were relatively isolated early in the study period, but expanded in size over time. The grouping analysis showed that regions with high NME use early in the study period were generally few (15% of all US Census tracts) and relatively isolated. Regions that had low initial NME use and moderate to large increases over the study period were located in close proximity to the initial high use regions. The grouping analysis also showed that roughly half of all tracts had 0% or very low NME use throughout the study period. CONCLUSIONS:We found an observable spatial structure to vaccine refusal and NME use over time, which appeared to be a self-reinforcing process, as well as a spatially diffusive process. Importantly, we found evidence that use of NMEs in the initially isolated regions appeared to stimulate vaccine refusal in geographically proximal regions. Thus, our results suggest that efforts aimed at decreasing future NME use may be most effective if they target regions where NME use is already high, as well as the nearby regions.

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Project description:ImportanceAlthough New York State (NYS) recently adopted legislation eliminating nonmedical vaccination exemption options from school-entry requirements, the implications of the law for school vaccine coverage and medical vaccine exemption uptake have not been examined.ObjectiveTo evaluate the implications of the repeal of school-entry nonmedical vaccination exemptions for vaccine coverage and medical exemption uptake at NYS schools outside of New York City (NYC).Design, setting, and participantsThis cohort study had an interrupted time-series design and used generalized estimating equation models to examine longitudinal school immunization compliance data from the 2012 to 2013 through 2021 to 2022 school years. The cohort comprised NYS public and nonpublic schools, excluding NYC schools, with any students enrolled in kindergarten to 12th grade. Eligible schools had enrollment and immunization data before and after the implementation of the Senate Bill 2994A legislation. Data analyses were conducted in July 2023.ExposureSenate Bill 2994A was passed in June 2019, eliminating school-entry nonmedical vaccination exemptions. Since compliance with the law was evaluated for most students during the next school year, the 2019 to 2020 school year was considered to be the law's effective date.Main outcomes and measuresThe primary outcomes were school vaccine coverage (defined as the percentage of students at each school who completed grade-appropriate requirements for all required vaccines) and medical exemption uptake (defined as the percentage of students at each school who received a medical exemption).ResultsAmong the 3821 eligible schools, 3632 (95.1%) were included in the analysis, representing 2794 (96.9% of eligible) public schools and 838 (89.2% of eligible) nonpublic schools. The implementation of Senate Bill 2994A was associated with absolute increases in mean vaccine coverage of 5.5% (95% CI, 4.5%-6.6%) among nonpublic schools and 0.9% (95% CI, 0.7%-1.1%) among public schools, with additional annual increases in vaccine coverage observed through the 2021 to 2022 school year. The law's implementation was also associated with a 0.1% (95% CI, 0.0%-0.1%) mean absolute decrease in medical vaccination exemption uptake at both public and nonpublic schools, and small but significant mean annual decreases in medical vaccination exemptions (0.02%; 95% CI, 0.01%-0.03%) through the end of the study period.Conclusions and relevanceResults of this cohort study suggested that repeal of school-entry nonmedical vaccination exemptions was associated with increased vaccine coverage at NYS schools outside of NYC. Coverage gains were not replaced by increases in medical vaccination exemptions.

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Dataset Information

Trends in medical and nonmedical immunization exemptions to measles-containing vaccine in Ontario: an annual cross-sectional assessment of students from school years 2002/03 to 2012/13.

Background

Methods

Results

Interpretation

Publications

Trends in medical and nonmedical immunization exemptions to measles-containing vaccine in Ontario: an annual cross-sectional assessment of students from school years 2002/03 to 2012/13.

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